#include "MyCode.h"
#include<iostream>
#include<vector>
#include<cmath>
#include<set>
using namespace std;
void day240329::day01() {
	int counts = 0;
	int n; cin >> n;
	for (int a = 1; a <= n; a++)
		if (a % 2 == 1 || a % 4 == 0)
			counts++;
	cout << counts << endl;
}